Many products are supplied in sealed bags, pouches or other packages formed from thin films or other flexible materials. For example, foodstuffs, tobacco products, small parts or loose items such as pharmaceuticals or medical accessories are commonly provided in pouches or bags formed from flexible film material. Many of these types of packages are provided with tear strips that facilitate opening the package. Moreover, it is known to provide resealing capability to such packages through the use of an adhesive disposed on a portion of the flexible package material that has been separated by the tear strip.
In some applications, it is desired to further construct the package or pouch to provide an indication of initial opening so that any tampering with the package or its contents may be discovered. Conventional tampering indicating devices include printed tapes that can be applied to the package and which are configured to reveal a message in the form of textural indicia, patterns or symbols when the tape seal is initially broken. Incorporation of such tamper indicating tapes increases the time and expense of manufacturing such packages.
Previous resealable packages have been constructed from two layers of flexible film material that are joined together. The first layer defines the outer packaging material and the second forms a panel or flap that can be separated from the first layer to expose an opening in the package. The first and second film layers typically are printed with graphics and indicia to indicate the contents of the package. One drawback of this type of packaging arrangement is that the first and second layers must be precisely registered prior to joining the layers, so that the printed indicia and graphics are in proper alignment on the finished package. The need to precisely register the film layers imposes additional requirements for automated packaging lines and may limit the operating speed of the equipment. Moreover, high scrap rates can result when the film layers drift out of register during operation.
A need therefore exists for a tamper-indicating resealable closure that does not increase the cost of packaging and which can easily be incorporated into the flexible materials used to form pouches, bags or other flexible packages.